Windup window shade with variable shading effect

ABSTRACT

A windup window shade is provided with windup window shade mechanism which, in the extracted state, make possible different degrees of opacity at the window. To this end, the two window shade web can either be wound on separate windup shafts and spread out in the same direction from the same starting point, or the two window shade webs have been connected with each other and, after having been extended, are moved in the manner of a film in front of the window. Two windup shafts are employed in both cases, wherein in the one case the two windup shafts are located directly next to each other, while in the other case the windup shafts are separated from each other during the extension of the shade.

CROSS REFERENCE TO RELATED APPLICATION

This application is a division of allowed U.S. application Ser. No.09/989,467 now Pat. No. 6,695,381 filed Nov. 21, 2001 the subject matterof which is incorporated herein by reference.

This application claims the priority of German Patent Application, 10057 764.4 filed Nov. 22, 2000.

BACKGROUND OF THE INVENTION

Modem automobile body shapes are distinguished by relatively largewindow areas. Because of strong sunlight, the large window areas resultin considerable heat generation in the interior of the vehicle and, inconnection with vehicles with air conditioning, this major heatgeneration results in a considerable use of energy in order tocounteract the heating effects on the vehicle.

For this reason, motor vehicles are increasingly equipped with windupwindow shades. A rear window windup shade is known from DE 36 12 165 A1,which has a windup shaft which is rotatably seated in a base. The baseis located on or underneath the rear window shelf. The window shade webof the rear window windup shade is pulled out from the rear window shelfin the direction toward the rear edge of the roof. The windup shaft,which is rotatably seated in the base and is biased by a spring drive inthe windup direction, is used for storing the unused part of the windowshade web. A traction rail is fastened on the edge of the window shadeweb remote from the windup shaft. With the aid of second pivot levers,the traction rail is transferred from a position in which it directlyadjoins the windup roller into a position in which the window shade webcovers nearly the entire window. For this purpose the pivot levers areessentially rigid in the direction perpendicular to that plane in whichthey move in the course of the retraction and extension of the windupshade.

Only two settings for light penetration through the rear window arepossible with the known blind. In one state light can enter unhamperedthrough the rear window, because the windup shade is completely wound onthe windup roller, while in the other state a reduction occurs inaccordance with the permeability to light of the windup shade web.

It is furthermore known to attach two guide rails laterally next to thewindow, in which the end of the traction rod of the window shade web isguided. The length of the traction rod is adjustable in order to be ableto accommodate various window widths. Actuation takes place by means ofthe thrust members running in the guide rails.

Only two states are possible here, too, namely the unhampered entry oflight or reduction in accordance with the reduction effects of thewindup shade web.

SUMMARY OF THE INVENTION

Based on the foregoing it is the object of the invention to create awindup window shade for motor vehicles, which allows a total of threeoperational states, wherein a different reduction of the entry of lightover the entire window area can be set.

It is possible by means of the windup window shade of the invention toachieve at least two additional shading states in addition to thecompletely unaffected light entry.

These different states can be achieved with window shade meanscomprising two window shade webs, which can be extended alternatively orsimultaneously.

In one of the embodiments, the window shade means of the windup windowshades are connected with each other along an edge, so that either nowindow shade web at all or one or the other window shade web can bepulled in front of the window. The other variation provides two windowshade webs, which are separate from each other and can be actuatedindependently of each other to the greatest extent.

One of the window shade webs can be made of a woven material or aperforated foil in order to permit light into the car interior in ametered manner. The other window shade web can be completely dark, orfor example also be provided with a metallized coating in order tocompletely block the entry of infrared light into the interior of thecar. Moreover, the opaque window shade web has the advantage ofpreventing a view of the car interior, which is advantageous inparticular in parked vehicles.

Guide means are assigned to the windup window shade means formaintaining the extended state. These guide means can consist of guiderails or pivot levers. The variation with the guide rails makes itpossible to cover the windows to the greatest extent. To this end twoguide rails extend next to the edges of the window, which follow thecontours of the window. At least one traction rod, sometimes called atraction rail herein, on which an edge of the respective window shadeweb is fastened, runs in these guide rails.

With the embodiment with two independent window shade webs, the guiderails have two guide grooves on each side, wherein one guide groove ofeach guide rail is assigned to the one window shade web, and the otherto the other window shade web.

So that the traction rails can follow the trapezoidal or convergingshape, the respective traction rail is embodied to be adjustable inlength.

The retraction and extension of the respective window shade web can takeplace in that the respective traction rail is driven by an electricmotor. Thrust or pressure members are provided for this, which are putin motion by the motor and move the ends of the respective traction railin the guide groove. The window shade webs are suitably biased in theretraction direction by means of spring drives.

The variation with two window shade webs can also be controlled verysimply with only a single motor. To this end, one end of thelinearly-shaped pressure member is coupled with the traction rail of theone window shade web, and the other end with the traction rail of theother window shade web. In other words, the return strand of the thrustmember on the part of one window shade web is at the same time thedriving strand on the part of the other window shade web. Cross-couplingis achieved in this way, which provides that both window shade webs areretracted in the center position of the thrust member. If the thrustmember is extended in the one direction, one of the window shade webs isextended, while during the extension in the opposite direction the otherwindow shade web is pulled out. In the center position both window shadewebs are retracted.

The thrust or pressure members are preferably approximately cylindricalstructures, which are provided with teeth on the exterior. Because ofthe approximately dynamically balanced design it is possible to overcomecurved guides easily. Such a thrust member is obtained if an essentiallycylindrical core is provided with a helically extending rib. Such thrustmembers are flexible shafts known in actual use under the commercialdesignation SUFLEX™ shafts.

Actuation of the individual window shade webs becomes simple if anindividual windup shaft is provided for each window shade web. Each oneof the windup shafts is biased in the retracting direction of therespective window shade web by its own spring drive.

To prevent the skewed pulling of the window shade web, which results inobliquely extending waves in the window shade web, it is practical toseat the respective windup shaft in a hoop, which itself is alsopivotable in respect to the drive direction, or to the guide rails,namely around an axis extending perpendicularly in respect to the axisof the windup shaft. An offset, which is created when the thrust membersin the respective guide rails are not exactly at the same effectiveheight, can be compensated by means of such seating. In this caseeffective height is understood to be the effective distance of the endof the thrust member from the axis of the windup shaft. Differenteffective heights would mean that on the one edge the traction rail ofthe respective window shade web would be forced to be at a greatereffective distance from the windup shaft than on the other edge, becauseof which the window shade web is deformed and tends to develop folds.

As already expressed at the outset, the option of achieving differentgrades of shade can also be created with the aid of pivot levers. Thepivot levers can either be simple rigid levers or toggle levers. Ineither case, one end of the levers is seated pivotable around shaftswhich extend at right angles in respect to the axis of the windup shaft.

A traction rod, on which a further windup shaft is rotatably seated, ismoved away from or toward the windup shaft with the aid of the pivotlevers. In this case the windup window shade means consist of two windowshade webs, fastened one behind the other in the direction of movementwhich, similar to a film in a camera, are moved back and forth betweenthe two windup shafts. In the last mentioned option it is necessary forthe leading window shade web to have a rectangular shape, so that it canbe completely wound on the respective windup shaft seated on thetraction rod. Because of the trapezoid window geometry, the traction rodas a rule is considerably shorter than would correspond to the width ofthe window in the lower area. Only the second window shade web can bematched to the trapezoidal window geometry.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the subject of the invention are represented inthe drawings.

FIG. 1 shows a passenger car in a rear view, showing a rear windowwindup shade in accordance with the invention in the extended state.

FIG. 2 shows the basic structure of the rear window windup shade inaccordance with FIG. 1.

FIG. 3 illustrates the guide rail of the rear window windup shade inaccordance with FIG. 1 in a cross-sectional view.

FIG. 4 illustrates the seating of the windup shafts of the rear windowwindup shade in accordance with FIG. 1 in a simplified schematicrepresentation.

FIG. 5 illustrates the drive mechanism of the rear window windup shadein accordance with FIG. 1 in a simple schematic representation.

FIG. 6 shows a passenger car in a perspective rear view illustratinganother exemplary embodiment of the rear window windup shade inaccordance with the invention.

FIG. 7 illustrates the rear window windup shade in FIG. 6 in aperspective general representation.

FIG. 8 illustrates the drive mechanism of the rear window windup shadein FIG. 6 in a greatly schematized perspective representation.

FIG. 9 illustrates a shunt for bringing together the guide grooves ofthe windup window shade in FIG. 2 in a greatly schematized perspectiverepresentation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In a schematic representation, FIG. 1 shows a rear view of a passengercar 1, having a roof 2, a trunk 3, as well as two C-pillars 4 and 5. Arear window opening 6, which is bordered at the top by a rear edge 7 ofthe roof and on the bottom by a lower window edge 8, is located betweenthe two C-pillars 4 and 5. A rear window pane is seated in the rearwindow opening 6 in a known manner, for example glued in by means of awindow rubber strip.

A rear window shelf 9 is located in the interior of the passenger car 1in front of the rear window, which extends between the lower window edge8 and the backrest of a rear seat, not visible in the drawing. Astraight outlet slit 11 extends in the rear window shelf 9.

The outlet slit 11 is a part of a rear window windup shade 12, whosebasic structure is shown, greatly schematized, in a lateral view in FIG.2.

The rear window windup shade 12 has two guide rails, which are fastenednext to the lateral edges of the rear window opening 6 on both C-pillars4 and 5. Because of the cut-open basic representation, only one guiderail 13, which for example is fastened on the C-pillar 5, can be seen inFIG. 2.

The guide rail 13 has the cross-sectional profile represented in FIG. 3.It is essentially square in cross section and is bordered by a front 14,two lateral walls 15 and 16, as well as by a back 17. A strip-likefastening flange 18 extends from the back 17, with the aid of which theguide rail 13 is to be attached to appropriate parts of the vehiclebody.

Two guide grooves 19 and 21, which are located parallel next to eachother, are circular in cross section and open via slits 22 and 23 towardthe front 14, are contained in the guide rail 13. The two guide grooves19 and 21 are identical in cross section and extend along the guide rail13 parallel and at equal distances.

The guide rail 13 is for example made of an extruded aluminum profile.

Since the slits 22, or 23 are narrower than the diameter of the circularsection of the guide grooves 19, or 21, undercut grooves are created,which are suitable for protecting a linearly shaped thrust memberagainst buckling and, by means of an appropriate cross section, toprevent the thrust member of an appropriate diameter from passingthrough the slit 22, or 23 to the outside.

The guide rails 13 are bent in respect to several axes so that theyfollow the contour of the window edge without becoming visible in thewindow itself. The guide rails 13 are arranged in such a way that thegrooves 19 and 21 are located one behind the other in the longitudinalextension of the vehicle, i.e. in relation to a vertical section throughthe vehicle, which follows the vehicle longitudinal axis, they lie nextto each other, so that the one guide groove is located toward the trunk3, and the other guide groove more toward the vehicle interior.

As FIG. 2 shows, the guide rails 13 extend downward through the slit 11to below the rear window shelf 9.

As indicated in FIG. 4, two windup shafts 25 and 26, sometimes referredto herein as windup rollers, which wind in opposite directions, arerotatably seated in a seating hoop 24. Each one of the windup shafts 25and 26 is tube-shaped and houses a spring drive. This spring drive forthe windup shaft 26 is schematically represented at 27 in FIG. 5. Thespring drive 27 consists of a helical spring, one end of which isfastened in the interior of the respective windup roller and the otherend of which is anchored to a seating hoop 24.

A window shade web 28 is fastened with one edge on the windup roller 25located toward the interior of the vehicle, whose shape is a trapezoidalapproximation of the contour of the rear window 6. The edge remote fromthe windup roller 25 is formed into a hose-shaped loop 29, in which atraction rod 31 is seated. The traction rod 31 consists of adimensionally stable tube 32, into which two L-shaped guide members 33and 34 have been inserted from both ends, as illustrated in FIG. 5.

The guide member 33 consists of a long leg 35, which can be displaced inthe dimensionally stable tube 32 and of a leg 36 which is angled off inan L-shape. The leg 35 is matched to the cross section of thedimensionally stable tube 32 and its dimensions are such that it canreach through the slit 22, or 23, into the interior of the respectiveguide groove 19 or 21. But the leg 36 is matched to the cross section ofthe circular part of the guide grove 19 or 21. In this way the leg 35can be longitudinally displaced in the dimensionally stable tube 32, andthe leg 36 can move along the respective guide groove 19, 21. It cannotbe pulled laterally out of the slit 22, 23.

The guide member 34 has the same structure as the guide member 33, sothat another explanation can be omitted.

A further window shade web 37 is attached to one end of the windup shaft26, which also forms a loop 38 at its edge remote from the windup shaft26. A longitudinally adjustable traction rail 39 is seated in the loop38. It consists of a dimensionally stable tube 41, whose lengthcorresponds to the edge and in which two guide members 42 and 43 areguided, which have the same structure as that extensively explained inconnection with the guide member 33.

The window shade webs 28 and 37 run off between the windup shafts 25,26.

The seating hoop 24 for seating the two windup shafts 25 and 26 is aU-shaped structure, having a rear element 44 and two legs 45 and 46extending at right angles therefrom, in which the windup shafts 25 and26 are rotatably seated by means of appropriate bearing journals.

A bearing journal 47 is located in the center of the rear element 44,whose axis extends at right angles to the axes of the two windup shafts25 and 26, which are axis-parallel with each other. The bearing journal47 is seated in a bearing bore 48 of a holder 49, which is fixedlyanchored in the vehicle underneath the rear window shelf 9. In this waythe two windup shafts 25 and 26 can rotate, limited in respect to theaxis defined by the bearing journal 47.

The middle position, i.e. the centered position, is defined by twocompression springs 51 and 52, one end of which is supported on theseating hoop 24, and the other on a rest 53 which is fixed in place onthe vehicle body and is schematically indicated. The two springs 51 and52 are seated on the transition point of the rear element 44 in therespective legs 45 or 46, so that equal torques are generated.

A drive mechanism 54, which is represented in a greatly schematizedmanner in FIG. 5, is provided for extending the window shade webs 28 and37. To simplify the representation and to make the understanding of theinvention easier, the two lateral guide rails 13 are represented rotatedin section in FIG. 5 in such a way that the two guide grooves 19 and 21are located next to each other in the drawing plane. As stated, thisillustration is merely provided for making understanding easier. Inactuality the two guide grooves 19 and 21 are located behind each otherand also open in the direction toward each other and not in thedirection toward the viewer.

A gear motor 55 is a part of the drive mechanism 54, which is composedof a permanently excited direct current (d.c.) motor 56 and a gearhousing. Two guide channels 58 and 59 are contained parallel to eachother in the gear housing, between which an output gear wheel 62 isprovided on an output shaft 61. The output gear wheel 62 can beselectively put into motion in both directions of rotation by means ofthe output shaft 61, which is connected with it fixed against relativerotation.

A guide tube 63 runs from the guide channel 58 to the lower end of theguide groove 19 in the right guide rail 13. A further guide tube 64connects the other end of the guide channel 58 with the lower end of theguide groove 21 in the left guide rail 13. At the right end, the guidechannel 59 is connected via a guide tube 65 with the lower end of theguide groove 21 in the right guide rail 13, and at the left end via aguide tube 66 with the lower end of the guide groove 19 in the guiderail 13. A flectionally elastic, linearly-shaped thrust member 67, or68, extends through the guide channel 58, as well as through the guidechannel 59. The lengths of the two thrust members 67 and 68 are of suchdimensions that, in the neutral position, they just do not project intothe associated guide grooves 19, or 21.

The two thrust members 67 and 68 are identically constructed. Eachconsists of an elastically flexible cylindrical core 69, which has oneor several ribs 71 on its exterior, which form a single- or multi-startscrew thread there. The ribs 71 protrude radially and run helically overthe cylindrical core 69 from one end of the thrust member to the otherend. The output gear wheel 62 has teeth which can enter between thegrooves formed by the ribs 71. In this way the output gear wheel 62 isinterlockingly coupled with the thrust members 67 and 68.

The mode of functioning of the described rear window windup shade is asfollows:

In the position of rest, the windup shafts 25, 26 have been rotated bythe action of the respective spring drives 27 into a position in whichthe window shade webs are wound up. In this position the hose-like loops29 and 38 are located in the outlet slit 11, as can be seen in FIG. 2.The guide members 33, 34 and 42, 43 are located in the vicinity of thelower ends of the two guide rails 13, but without the legs 36 havingbeen released out of the associated guide grooves 19 and 21. For theguide members 42 and 43 this position is shown in FIG. 5. The guidemembers 33 and 34 take up a similar position and, if they had been drawnin FIG. 5, would be concealed by the guide members 42 and 43.

At the same time the two ends of the thrust members 67 and 68 are spacedapart from the respective legs 36.

If, starting from this position of the rear windup window shade 12, inwhich the entry of light into the vehicle interior is not hampered atall, the user would like to create a first shading effect, he wouldextend the window shade web 28, for example. The window shade web 28reduces the entry of light, but without stopping it completely. For thispurpose the window shade web 28 is made, for example, of an open chainweave, or a perforated plastic foil, which is colored black.

To extend the window shade web 28, the gear motor 55 is put intooperation in a direction of rotation in which it moves the thrust member67 toward the right through the guide groove 19. Since the two thrustmembers 67 and 68 mesh with the output gear wheel 62 at diametricallyopposite ends, the thrust member 68 is simultaneously pushed forwardtoward the left through the guide groove 19 and the left guide rail 13.After a short distance over the advance path, the free ends of the twothrust members 67 and 68 come into engagement with the lower ends of thelegs 36 of the two guide members 33 and 34, and in the further processpush the guide members 33 and 34 in the direction toward the upper endof the two guide rails 13.

Since the distance between the guide rails changes, the legs 35 of theguide members 33 and 34 simultaneously dip into the dimensionally stabletube 33 of the traction rail 31 contained in the respective loop 29.

As soon as the end position has been reached, the gear motor 55 isstopped. The gear motor 55 is self-locking and arrests the thrustmembers 67 and 68 in their respectively reached positions.

The switch-off of the gear motor 55 is performed with the aid of limitstop switches, or in that the guide members 33 and 34 run up againststops, so that a blocking current occurs, which is evaluated in anelectronic device and leads to switch-off.

The window shade web 28 is now held stretched between the traction rail31 and the respective windup shaft 25.

For retraction, the gear motor 55 is started in the opposite directionof rotation, so that the two guide members 67 and 68 are moved downwardout of the associated guide rails 13. The traction rail 31simultaneously moves downward, because the window shade web 28 isconstantly kept under tension by the action of the spring drive 27 ofthe windup shaft 25.

As soon as the window shade web 28 is completely wound, the ends of thetraction members 67 and 68 are freed from the guide members 33 and 34.This centered middle position can also be detected by limit stopswitches and results in the stop of the gear motor 55.

If, following the complete retraction of the window shade web 28, thegear motor 55 remains switched on in the same direction of rotation, thethrust member 67 is pushed forward in the guide grove 21 of the leftguide rail 13, and the thrust member 68 in the guide groove 21 of theright guide rail 13. Since the traction rail 39 of the other windowshade web 37 is conducted in the guide grooves 21, now this tractionrail 39 is taken along by the two thrust members 67 and 68. The resultof this is that now the window shade web 37 is stretched in front of therear window.

The window shade web 37 has a different transparency to light than thewindow shade web 28. For example, the window shade web 37 can becompletely opaque, so that any entry of light into the vehicle interioris prevented. Such an operating position is particularly advantageouswhen the car is parked, because it is possible by means of this toprevent the heating of the interior by the radiation of light throughthe rear window.

The entry of heat by radiation can be further reduced if the outwardfacing side of the window shade web 37 is additionally metallized forreflecting infrared radiation.

Retraction of the window shade web 37 takes place in the respectivelyopposite manner.

Since because of assembly tolerances it is not always assured that thethrust members 67 and 68 lift the respective traction rail 31 or 39exactly parallel in respect to the associated windup shaft 25 or 26,tilting of the respective traction rail 31 or 39 in respect to theassociated windup shaft 25, 26 can occur. Without corrective action, thetilting would lead to obliquely extending waves or folds in therespective window shade web. However, since the two windup rollers 25and 26 are pivotably received in the seating hoop 24, the windup shaftcan align itself in a limited manner obliquely, and therefore bepositioned exactly parallel with the respective traction rail 31, 39.Obliquely extending tension in the window shade web is prevented.

The hoop is biased into the centered position with the aid of the twosprings 51 and 52. Tumbling of the hoop around the transverse axis, andtherefore clattering of the hoop during driving is prevented.

A further exemplary embodiment of the rear windup window shade 12 isrepresented in FIGS. 6-8. To the extent that already describedcomponents are repeated there, they are provided with the same referencenumerals and will not be explained again.

In accordance with FIG. 6, a windup window shade means 77, which iscomposed of two window shade webs 78 and 79, which are connected witheach other along a connecting line 80, are part of the rear windupwindow shade 12. The window shade web 78, which can be partially seen,is rectangularly cut and lets more light through than the window shadeweb 79, which is cut in a trapezoidal shape.

The windup window shade means 77 is maintained stretched with the aid oftwo pivot levers 81 and 82. For this purpose the pivot levers 81 and 82act on a pull-out rail, or traction rod, 83.

FIGS. 7 and 8 show in detail the construction of the rear windup windowshade 12 of FIG. 6. The traction rod 83 is provided with a groove 84which is open toward the bottom and is slidingly engaged by the freeends of the two pivot levers 81 and 82, which can be pivoted in oppositedirections. During the retraction and extension of the rear windupwindow shade 12, the pivot levers 81 and 82, together with the windupwindow shade means 77, move out of, or into the outlet slit 11.

A base 85 is attached below the rear window shelf 9, which contains alongitudinal groove 86, in which a windup shaft 87 is rotatably seated.To this end, one end of the base is provided with a seating element 88,and the other end with a gear motor 89, on whose output shaft the windupshaft 87 is seated, fixed against relative rotation.

The windup window shade means 77 is fastened with one edge on the windupshaft 87.

Two bearing blocks, of which only the bearing block 90 can be seen inFIG. 8 for reasons of representation, are fastened on the underside ofthe traction rod 83. A further windup shaft 91 is rotatably seated,fixed against relative rotation, between the bearing blocks 90. Thewindup shaft 91 is tube-shaped and houses a spring drive 92 in the formof a helical spring in its interior. The same as the helical spring 27,one end of the helical spring is connected, fixed against relativerotation, with the windup shaft 91, while its other end is immovablyconnected with the bearing block 90.

The windup window shade means 77 is maintained stretched between thewindup shaft 87 and the windup shaft 91, wherein the spring drive 92takes care of the biasing.

Two angular gears 93 and 94 are located at a distance from each other onthe base 85. The angular gear 94 has an output shaft 95, on which thepivot lever 82 is seated, fixed against relative rotation. An electricmotor 96 is connected to the input side of the angular gear 94, so thatthe output shaft 95 can be selectively caused to rotate. A clutch shaft97 connects an extension of the input shaft of the angular gear 94 withthe input of the angular gear 93.

The angular gear 93 also has an output, or bearing shaft 99, to whichthe pivot shaft 81 is attached, fixed against relative rotation. Theshafts 95 and 99 lie parallel with each other and at right angles inrespect to the longitudinal extension of the windup shaft 87. Theyrespectively rotate in opposite directions.

To explain the mode of operation of the rear windup window shade 12 itshould be assumed that the pivot levers 81 and 82 are in their positionof rest, in which they extend approximately parallel in respect to thewindup shaft 87. The windup shaft 87 has been rotated in such a way thatthe windup window shade means 77 are wound on the windup shaft 87 as faras the connecting line 80. With this, the window shade web 79 isessentially wound on the windup shaft 87.

If, proceeding from there, the motor 96 is energized and begins torotate, the pivot levers 81 and 82 are raised in opposite directions,wherein initially they lift the traction rod 83 resting on the outletslit 11 and conduct it in the direction toward the rear roof edge 7. Thegear motor 89 is switched off and, based on the movement of the tractionrod 83 away from the windup shaft 87, the window shade web 78 is unwoundfrom the windup shaft 91 against the action of the spring drive 92. Inits end position, the traction rod 83 extends closely below the rearroof edge 7, as shown in FIG. 6, and a rectangle corresponding to thewidth of the traction rod 83 is shaded by the window shade web 78.

If the user desires greater shading than that corresponding to theopacity of the window shade web 78, he switches on the gear motor 89,which thereupon rotates the windup shaft 87. The window shade web 79 isunwound from the windup shaft 87 by means of this, while the springdrive 92 takes care of winding the window shade web 78 up to the sameextent. The end position is achieved when the connecting line 80 hasarrived at the windup shaft 91. When this stage, which can be sensed byswitches, is reached, the gear motor 89 is automatically stopped.

The rear window is now shaded by the window shade web 79, which moreoverpermits a trapezoidal approximation of the window geometry.

For retraction, by switching on the gear motor 89 first a stage is set,in which the window shade web 79 is completely wound on the windup shaft87. After this stage has been reached, the electric motor 96 is put intooperation in the direction of pivoting the levers 81 and 82 in.

It should be noted that all drawings are schematic and not to scale. Ifnevertheless the distance between the bearing shafts 95 and 99 is lessthan would correspond to the sum of the two pivot levers 81 and 82, itis easily possible to let the two pivot levers 81 and 82 run in separategrooves, so that their ends do not collide with each other.

Aside from the pivot levers shown, solutions are also conceivable inwhich the two pivot levers 81 and 82 would be respectively replaced bytoggle levers. The lower arm of each toggle lever would then befastened, fixed against relative rotation, on the shaft 95, or 98, whilethe upper arm is hinged on the traction rod 83. The two arms of eachtoggle lever would then be connected with each other by a toggle leverhinge.

FIG. 9 shows an alternative embodiment of the guide means for guidingthe traction rods 31 and 39 in the exemplary embodiment in accordancewith FIGS. 1 to 5 in a simplified way.

While in the exemplary embodiment in accordance with FIGS. 2 and 5 twoguide grooves 19, 21 are contained in each guide rail 13, which extendover the entire length, the exemplary embodiment in accordance with FIG.9 only has one guide groove 101 in the guide rail 13. At its end towardthe windup shaft, the guide rail 13 makes a transition into a shunt 102,in which the guide groove 101 is split into two guide grooves 19 and 21.As in the exemplary embodiment of FIG. 5, the guide tubes 63 to 66terminate in the analogously identical manner in the extension of thetwo guide grooves 19 and 21.

In the exemplary embodiment represented, the guide groove 21 extendsessentially in a straight line and terminates without a curve in theguide groove 101, while the guide groove 19 represents the fork out ofthe guide groove 101 and terminates coming from the side.

In order to let the traction rods 31 and 39 enter into the respectivelycorrect guide groove 19, or 21, a pivotably seated shunt tongue 103 isprovided. The shunt tongue 103 is seated at shaft 104 and is pivotablearound a shaft which lies parallel with the axes of the two windupshafts 25 and 26. The shaft 104 is located on the tongue 103 of theshunt 102 directly before the two grooves 19 and 21 meet.

The shunt tongue 103 represents a two-armed lever with a first section105 and a second section 107, which contains a hook 106.

The shunt operates as follows:

In the position of rest, when both window shade webs 28 and 37 areretracted, the traction rod 39 lies in the hook 106 and pivots the shunttongue 103 in a counterclockwise direction in accordance with FIG. 9.The pivot is sufficient for letting the section 105 complement thecurved path at the transition from the groove 19 to the groove 101 withits guide face 108. In this position the section 105 rests against astop 109.

The traction rod 31 can now be pushed away from the windup shaft 25 viathe respective thrust member 67 or 68, which is guided by means of theguide tube 63, or 66. In the course of this the guide rod 31 moves aftera short distance out of the guide groove 19 into the common guide groove101.

During retraction, the traction rod 31 runs along the guide face 108 andby means of this is returned into the groove 19 in the further course ofthis.

When the window shade web 37 is extended, the traction rod 39 moves outof the hook 106, so that the shunt tongue 103 rests with its guide face108 against a stop 111 because of the action of a spring, not furtherrepresented. In this position a guide face 112, which is essentiallylocated opposite the guide face 108, closes the inlet into the guidegroove 19.

FIG. 9 represents the state directly after the traction rod 39 hasentered the guide groove 101, or the state directly prior to thetraction rod 39 passing the guide groove 19 when entering the mouth ofthe guide groove 21.

Now the window shade web 37 can be extended and also retracted again aspreviously described. The shunt tongue 103 sees to it that the tractionrod 39 comes to rest in the correct guide groove 21 after passing thebranch point.

The window shade webs are represented in connection with a rear window.However, it is understood that the windup window shade solution can alsobe applied in connection with any other window of a passenger car.

Windup window shade is provided with windup window shade means which, inthe extracted state, make possible different degrees of opacity at thewindow. To this end, the two window shade webs can either be wound onseparate windup shafts and spread out in the same direction from thesame starting point, or the two window shade webs have been connectedwith each other and, after having been extended, are moved in the mannerof a film in front of the window. Two windup shafts are employed in bothcases, wherein in the one case the two windup shafts are locateddirectly next to each other, while in the other case the windup shaftsare separated from each other during the extension of the shade.

1. A windup window shade for regulating the entry of light through awindow into the interior of a motor vehicle, comprising: windup windowshade means, comprising first and second window shade webs that areseparate from each other, which can be brought into first, second andthird different operational states, wherein in the first operationalstate no reduction of the entry of the light takes place, in the secondoperational state a reduction of the light entering the interior takesplace, and in the third operational state a reduction of the light takesplace which differs from the first and second states, drive mechanismsdesigned for taking the windup window shade means from one of saidoperational states into another of said operational states, storagemeans for storing the windup window shade means in at least one of saidoperational states, and, guide means forming a pair of first guidegrooves extending for a distance along a side of the first window shadeweb, when extended, for guiding a first traction rod, and a pair ofsecond guide grooves extending for a distance along a side of the secondwindow shade web, when extended, for guiding a second traction rod, andthe first guide grooves and the second guide grooves terminate in anassociated shunt, from which only one said guide groove continues, withthe only one said guide groove extending for a further distance along arespective window edge.
 2. The window windup shade in accordance withclaim 1, wherein one of the window shade webs comprises a woven materialor a perforated foil.
 3. The window windup shade in accordance withclaim 1, wherein one of the window shade webs is essentially completelyopaque.
 4. The window windup shade in accordance with claim 1, whereinone of the window shade webs is metallized on the side facing away fromthe interior of the vehicle.
 5. The window windup shade in accordancewith claim 1, wherein the guide means maintains the windup window shademeans in the extended state.
 6. The window windup shade in accordancewith claim 3, wherein the guide means comprises two guide railsextending laterally next to edges of the window shade webs in theextended state of the windup window shade means.
 7. The window windupshade in accordance with claim 5, wherein the traction rods areadjustable in length.
 8. The window windup shade in accordance withclaim 5, wherein each window shade web has an edge having a respectivesaid traction rod moving along an essentially elongated path when thereis a change in one of said operational states.
 9. The window windupshade in accordance with claim 1, wherein the drive mechanisms compriseat least one gear motor, by means of which a flexible linearly-shapedthrust member can be selectively moved in the longitudinal direction,one end of the thrust member acting together with an end of one of thetraction rods.
 10. The window windup shade in accordance with claim 7,wherein two of said linearly-shaped flexible thrust members areprovided, the thrust members being movable in opposite directions by theat least one gear motor, wherein one end of one of the thrust membersacts together with one end of the traction rod of the first window shadeweb, and the other end of said one of the thrust members acts togetherwith one end of the traction rod of the second window shade web, andthat said two thrust members act together with the ends of the tractionrods of the window shade webs.
 11. The window windup shade in accordancewith claim 7, wherein each of the thrust members is an approximatelycylindrical structure provided with teeth on the exterior.
 12. Thewindow windup shade in accordance with claim 9, wherein the teeth areformed by a rib extending helically on the exterior.
 13. The windowwindup shade in accordance with claim 7, wherein the thrust members actinterlockingly together with the at least one gear motor.
 14. The windowwindup shade in accordance with claim 1, wherein one windup shaft isprovided for each said window shade web, with an edge of a respectivesaid window shade web being fastened to a respective said windup shaft.15. The window windup shade in accordance with claim 12, wherein eachsaid windup shaft has a respective spring drive, by means of which therespective windup shaft is spring-biased in the direction of winding upthe respective window shade web.
 16. The window windup shade inaccordance with claim 12, wherein ends of at least one of the windupshafts are seated in a seating hoop, which is seated, pivotable withrespect to an axis of the vehicle, on a base adapted to be fixed to thevehicle, wherein the axis extends at right angles to the respectivewindup shaft.
 17. The window windup shade in accordance with claim 14,wherein the seating hoop is elastically biased toward a centeredposition by spring means.